What is Congenital Erythropoietic Porphyria (CEP)?
CEP is very rare and caused by changes in the UROS gene which results in low levels of the UROS enzyme in the heme pathway. The low levels of the UROS enzymes in the bone marrow, where red blood cells are made, results in the accumulation of porphyrins in the body because there isn’t enough UROS enzymes to process them.
Porphyrins accumulate, particularly in the skin, bone marrow, teeth, and bones. Exposure to sunlight and some forms of artificial light activates the accumulated porphyrins in the skin and causes in severe blistering.
What are the symptoms of Congenital Erythropoietic Porphyria?
Symptoms include:
- Blistering on light-exposed parts of the body, most commonly the hands, arms and face
- Fluid-filled blisters can rupture and become infected, leading to scarring, bone loss and deformities
- Increased hair growth on sun-exposed skin
- Brownish-colored teeth (erythrodontia)
- Reddish-colored urine
- Bone fragility and vitamin deficiencies, especially vitamin D
- Enlarged spleen
How is Congenital Erythropoietic Porphyria diagnosed?
CEP is diagnosed using biochemical testing, starting with testing plasma and urine for elevated porphyrins. Additional testing is required to rule out other reasons that porphyrins may be high (ex. lead exposure) and other types of porphyria.
What are treatments for Congenital Erythropoietic Porphyria?
Anemia
In people with severe anemia, repeated red blood cell transfusion are needed. In severely affected people who are dependent on blood transfusions, a bone marrow transplant may be needed. People who have successful bone marrow transplants no longer have sun-sensitivity.
Potential Treatments under Development
Medications to treat CEP are currently being researched, and a clinical trial is expected to begin recruiting in the upcoming year.
How is Congenital Erythropoietic Porphyria managed?
People with CEP should see a porphyria specialist at least once a year for regular follow-up. People who have severe anemia may need to see a specialist more regularly.
Light Avoidance
Avoiding exposure to sunlight is the most important way to manage symptoms for people with CEP. People with CEP need to wear protective clothing, and have windows tinted in their cars and homes. Most sunscreens are not effective because they do not block light in the blue-violet range, which is the type of light that triggers reactions in porphyria.
Blister/Wound Care
There is a high risk of developing infections in blisters, particularly if they rupture. Prescription antibiotic ointments may be required to manage infections. Care from a dermatologist is recommended.
How is Congenital Erythropoietic Porphyria monitored? Are there long-term complications?
Photomutilation can result in the loss of facial features (nose, ear and lids) and digits. Hypertrichosis on sunexposed skin, reddish-brown colored teeth (erythrodontia), and reddish-colored urine are common features. There may be bone fragility due to expansion of the bone marrow and vitamin D deficiency. In severe causes, erythrocytes have a shortened life-span, and mild or severe hemolytic anemia results, along with increased erythroid synthesis and splenomegaly.
How is Congenital Erythropoietic Porphyria inherited?
CEP is inherited as an autosomal recessive genetic disorder. Recessive disorders occur when an individual inherits two copies of an abnormal gene for the same trait or disease, one from each parent. Typically, there is no family history of the disease (except possibly in siblings), and neither parent has symptoms, but each carries a changed gene that they can pass to their children. The risk for two carrier parents to both pass the changed gene and have an affected child is 25% with each pregnancy. If an individual receives one normal gene and one changed gene, the person will be a carrier for the disease, and will not have any symptoms.